Effective early intervention depends on reliable screening of risk for communication impairments as soon as possible. Established infant communication risk factors include poor attention, gestures, social connectedness, exploratory play, and speech. Although these risk factors can be detected by 12-18 mos. and reliably predict later language and social disorders, attempts to detect similar risk factors in infants 2-1 mos. have been unsuccessful because of limitations in available screeners that include only 2-3 items for preintentional communication (i.e., reactive or active infant communication behaviors not directed toward listeners). There are no available screeners that provide normed and sensitive data on preintentional communication and reflect evidence-based predictors that discriminate infants at risk for communication impairments before 12 mos. When practitioners cannot detect infant behaviors known to be associated with communication risk, they cannot target early intervention to children with the greatest needs and potential for improvement. If we can identify communication risk early enough, we can intervene in skills that predict communication impairments, mitigate effects of primary impairments in children, and reduce potential for secondary impairments that affect communication and other life skills. The plan for this project is to refine and norm a predictive, sensitive, modality-independent screener to detect communication risk in preintentional infants 2-12 mos. (Communication in Infants and Social Screener, or CISS). Phase I research by the Principal Investigator showed that the CISS is an internally consistent measure to reliably identify preintentional risk factors in infants 2-12 months who later show communication impairments. The easy qualitative judgments on the CISS have been derived from the PI's comprehensive assessment of preintentional infant communication, the Infant Social and Communication Behavior Scales (ISCBS), and correspond to behavior clusters for the leading toddler communication assessment, the Communication and Symbolic Behavior Scales Development Profile-Infant-Toddler Checklist (CSBS DP-ITC); Wetherby & Prizant, 2002). A sensitive and specific screener for communication risk could justify the early involvement of speech-language pathologists for infants as well as for older children with complex communication needs. We will revise and norm the Phase I CISS to detect communication risk factors in infants 2-12 mos. with and without known disabilities, test new samples of over 350 TD and over 150 at-risk preintentional infants at 2-12 mos., and administer the CISS through pediatrician well-baby visits to achieve these specific aims: Establish the reliability, validity, and age-based norms of the scales, domains, and composite scores for the CISS in nationally representative samples of typically developing infants using correlational analyses, including confirmatory factor analysis; demonstrate the efficacy of the CISS at discriminating communication risk factors associated with disability in high-risk infants as well as infants without known risk; and establish the feasibility and efficacy of CISS administration through pediatrician well-baby visits.